+The importance of marriage for the health to married persons+ is shown by figure C 102--"+condition with regard to marriage and mortality in Prussia, 1894-97+," as given in Prinzing's book. That we have to deal here with an actual favourable influence of marriage, and not with a selection of the healthy at the time of marriage, is proved by the fact that the low death rate of the married is maintained through all age classes and that the widowed and divorced show throughout the highest death rate. [Sidenote: C 103] "+Condition with regard to marriage and mortality, cases of death from tuberculosis+," after Weinberg, also confirms with regard to tuberculosis the favourable influence of marriage on the health of men. With women the mortality from tuberculosis up to the age of 60 is lowest among the unmarried. Pregnancy and suckling act here adversely, but by far the worst position is also held here by widows and divorced women. [Sidenote: C 104-105] The advantage of marriage for the progeny is made evident in Figure C 104--"+mortality of illegitimate children in different European states+", and in Figure C 105 dealing with the "+survival of the legitimate and illegitimate children in Berlin in 1885+." After five years there are still alive more than 60% of the legitimate, but only 40% of the illegitimate children. The higher mortality of the latter is by no means a purifying process of weeding, but the expression of greater sickliness which permanently harms the surviving also. The division of labour between man and wife, with reference to the care of the offspring, is one of Nature's institutions which is of the greatest advantage for parents as well as children. [Sidenote: C 106-107] +Inbreeding and the Crossing of Races.+ On the whole with mankind inbreeding is viewed with fear, and justly so, in view of our customary carelessness with regard to the physical and mental conditions of those who contract marriage. +If blood relations have similar pathological conditions or pre-dispositions to illness or degeneracy, the progeny which results from their union is endangered to a particularly high degree.+ Our collection brings as an example of this in Table C 106--the pedigree of the celebrated Don Carlos. The bad inheritance of Johanna the Mad asserts itself to a lesser degree yet quite perceptibly also in the children of Max. II. Table C 107--the children of Maximilian and his cousin Maria of Spain; undoubtedly the Emperor Rudolf II. was mentally diseased. Also Charles V. and his son Philip II. were abnormal characters. [Sidenote: C 108] +Blood relationship of the parents and health of the children+, which v. d. Velden has prepared from Riffel's family tables, also speaks for the harmfulness of inbreeding. The offspring of blood relations are emphatically weaker and sicklier than those of persons related distantly or not at all. [Sidenote: C 109]